# operator+,-(ranges::transform_view::iterator)

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< cpp‎ | ranges‎ | transform view‎ | iterator

friend constexpr /*iterator*/ operator+( /*iterator*/ i, difference_type n ) requires ranges::random_access_range<Base>; | (1) | (since C++20)
friend constexpr /*iterator*/ operator+( difference_type n, /*iterator*/ i ) requires ranges::random_access_range<Base>; | (2) | (since C++20)
friend constexpr /*iterator*/ operator-( /*iterator*/ i, difference_type n ) requires ranges::random_access_range<Base>; | (3) | (since C++20)
friend constexpr difference_type operator-( const /*iterator*/& x, const /*iterator*/& y ) requires std::sized_sentinel_for<ranges::iterator_t<Base>, ranges::iterator_t<Base>>; | (4) | (since C++20)

1,2) Returns the iterator i incremented by n.
3) Returns the iterator i decremented by n.
4) Returns the distance between x and y.

These functions are not visible to ordinary unqualified or qualified lookup, and can only be found by argument-dependent lookup when `transform_view::iterator<Const>` is an associated class of the arguments.

### Parameters

i, x, y | - | the iterators.
n | - | position relative to current location.

### Return value

Let `parent_` denote the pointer to the parent `transform_view`, `current_` denote the underlying iterator.

1,2) /*iterator*/{*i.parent_, i.current_ + n}
3) /*iterator*/{*i.parent_, i.current_ - n}
4) x.current_ - y.current_

### Example

| This section is incomplete Reason: no example

### Defect reports

The following behavior-changing defect reports were applied retroactively to previously published C++ standards.

DR | Applied to | Behavior as published | Correct behavior
--- | --- | --- | ---
LWG 3483 | C++20 | `transform_view::iterator`'s difference is overconstrained | requirement is relaxed

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